Daylight Saving Time (DST) began at 2am on Sunday, Mar. 11, 2018 with "spring forward" when most of the United States moved clocks forward by one hour, and ends at 2am on Sunday, Nov. 4, 2018 when those clocks will "fall back" one hour.

DST was implemented in the United States nationally on Mar. 31, 1918 as a wartime effort to save an hour's worth of fuel (gas or oil) each day to light lamps and coal to heat homes. It was repealed nationwide in 1919, and then maintained by some individual localities (such as New York City) in what Time Magazine called "a chaos of clocks" until 1966 when the Uniform Time Act made DST consistent nationwide. [8]

Approximately 1.5 billion people in 70 countries observe DST worldwide. [26][29] In the United States, 48 states participate in Daylight Saving Time. Arizona, Hawaii, some Amish communities, and the American territories (American Samoa, Guam, Puerto Rico, the Virgin Islands, and the Northern Mariana Islands) do not observe DST. [8] In the first quarter of 2018, bills were considered in at least 13 state legislatures to amend DST or exempt individual states from DST. [33] 33% of Americans think DST is worth the effort, while 48% do not and 19% are not sure. [20]

People in favor of keeping Daylight Saving Time say it allows drivers to commute more safely in daylight, promotes outdoor activities, and stimulates the economy. Those who oppose Daylight Saving Time say that the change is a harmful disruption to health and work productivity, and is expensive. While the time change was initially implemented to save energy, studies are mixed and have found our current use of air conditioning and heating may negate the energy saved by not having to use electric lights and may actually increase electricity usage. [24][25] Read on for pros and cons in the debate on Daylight Saving Time.

Should the United States Keep Daylight Saving Time?

Pro 1

Daylight Saving Time's (DST) Longer Daylight Hours Promote Safety. Longer daylight hours make driving safer, lowers car accident rates, and lowers the risk of pedestrians being hit by a car. [3][30] Economists Jennifer Doleac, PhD, and Nicholas Sanders, PhD, found that robberies drop about 7% overall, and 27% in the evening hours after the spring time change. [17][22] They stated, "Most street crime occurs in the evening around common commuting hours of 5 to 8 PM, and more ambient light during typical high-crime hours makes it easier for victims and passers-by to see potential threats and later identify wrongdoers." [17] Also, daylight in the evening makes it safer for joggers, people walking dogs after work, and children playing outside, among others, because drivers are able to see people more easily and criminal activity is lowered.

Con 1

Daylight Saving Time (DST) Is Bad for Your Health. Changing sleep patterns, even by one hour, goes against a person's natural circadian rhythms and has negative consequences for health. [1] One study found that the risk of a heart attack increases 10% the Monday and Tuesday following the spring time change. [2] Researchers found an increase in cluster headaches (sudden and debilitating headaches) after the fall time change. [15] James Wyatt, PhD, Associate Professor at Rush University Medical Center, stated, "We're encountering an increase in extra auto and workplace accidents on Monday or perhaps even carrying through the first week of the Spring time shift." [1] In the weeks following the spring DST time change, male suicide rates rose in Australia compared to the weeks following the return to standard time in the fall. [4] DST increases the risk that a car accident will be fatal by 5-6.5% and results in over 30 more deaths from car accidents annually. [29]

Pro 2

DST Is Good for the Economy. Later daylight means more people shopping after work, increasing retail sales, and more people driving, increasing gas and snacks sales for eight months of the year (the time we spend in DST). [2][18][19] The golf industry reported that one month of DST was worth $200 to $400 million because of the extended evening hours golfers can play. [2] The barbeque industry estimated their profits increase $150 million for one month of DST. In 2007, an estimated $59 million was saved because fewer robberies were committed thanks to the sun being up later. [3] Chambers of Commerce tend to support DST because of the positive effect on the economy. [21] Consumer spending increases during DST, giving the economy a boost. Compared to Phoenix, Arizona, which does not have DST, Los Angeles, California, shoppers spent 3.5% less at local retailers after DST ended in the fall. [31]

Con 2

DST Drops Productivity. The Monday after the spring time change is called "Sleepy Monday," because it is one of the most sleep-deprived days of the year. [23] The week after the spring DST time change sees an increase in "cyber-loafing" (employees wasting time on the internet) because they're tired. [5] Dr. Till Roenneberg, a German chronobiologist, who studies the body's relationship with light and dark, notes that the human circadian clock doesn't adjust to DST and the "consequence of that is that the majority of the population has drastically decreased productivity, decreased quality of life, increasing susceptibility to illness, and is just plain tired." [2]

Pro 3

DST Promotes Active Lifestyles. When the day is lighter later, people tend to participate in more outdoor activities after work. [14] Hendrik Wolff, PhD, Associate Professor of Economics at Simon Fraser University, stated, because of DST "people engaged in more outdoor recreation and less indoor-TV watching… An additional 3 percent of people engaged in outdoor behaviors who otherwise would have stayed indoors." [2] Michael Downing, author of Spring Forward, stated, "Baseball [was] a huge early supporter, too, because there [was] no artificial illumination of parks, so [they could] get school kids and workers to ball games with the extended daylight, they have a later start time." [12]

Con 3

DST Is Expensive. William F. Shughart II, PhD, Economist at Utah State University, states that the simple act of changing clocks costs Americans $1.7 billion in lost opportunity cost based on average hourly wages, meaning that the ten or so minutes spent moving clocks, watches, and devices forward and backward could be spent on something more productive. [2] The Air Transport Association estimated that DST cost the airline industry $147 million dollars in 2007 thanks to confused time schedules with countries who do not participate in the time change. [1] According to the Lost-Hour Economic Index, moving the clocks forward has a total cost to the US economy of $434 million nationally, factoring in health issues, decreased productivity, and workplace injuries. [32]

Did You Know?

Benjamin Franklin is often credited with the idea of DST because, in a satirical letter to the authors of The Journal of Paris, he suggested the French wake earlier to take advantage of "using sunshine instead of candles." [6][7][8]

DST as we know it was proposed by a New Zealand entomologist, George Vernon Hudson, who wanted longer hours for insect study. [28]

The first locality to enact DST was Port Arthur (now Thunder Bay, Ontario), Canada, in 1908. The first country to enact DST was Germany on Apr. 30, 1916, although the Germans dropped the time change at war's end. [6][8]

American farmers were opposed to DST because, regardless of what the clock said, their cows weren't ready to be milked until later in the day during DST. [1][8]

A resort in Madagascar created its own DST, which runs an hour ahead of the rest of the country, so the lemurs would "naturally join us in the Oasis garden… for the '5 O’clock tea.'" [9]

Some ancient civilizations are known to have used practices similar to DST. Roman water clocks, for example, used different scales for different times of the year. [10]